The erasing properties of amorphous Ge_2Sb_2Te_5 phase change films are studied by using blue-green laser. Blue-green lasers with 1000ns, 500ns, 100ns, and 60ns pulse duration are selected in the experiment. The results show that reflectivity contrast increases with the laser power increases. Within the time with 1000ns,500ns,100ns,60ns range, the amorphous films change to the crystalline phase. Erasing power higher than 4.49mW, the reflectivity contrast of films irradiation upon blue-green laser with 60ns is higher than 15%, which indicates Ge_2Sb_2Te_5 films have the high crystallization speed under the condition of short pulse duration and low erasing power. And also the optical spectra properties between amorphous and crystalline phases are analyzed. Compare to the reflectivity and the reflectivity contrast of amorphous and crystalline phases films at different wavelength with 780nm,650nm,514nm and 405nm, and present the future improving way to Ge_2Sb_2Te_5 films applied in the blue –ray disc.